1. Field of the Invention
The present invention relates generally to content filtering systems, and more particularly but not exclusively to content filtering systems operable on mobile phones.
2. Description of the Background Art
Mobile wireless devices facilitate communication between individuals, and dissemination of information in general. Some mobile wireless devices, such as mobile phones, even have the capability to receive not just voice communications but text messages as well. Text messaging has become very popular because of its relatively low cost of operation and convenience. As a result, mobile phones that are operable to receive Short Message Service (SMS) text messages are widely commercially available.
Malicious individuals, such as fraudsters, hackers, and spammers, are quick to take advantage of the anonymity and fast communication provided by wireless telephone networks. Just like on the Internet, these malicious individuals may send phony messages to advance fraudulent schemes (commonly known as “phishing”), unsolicited messages (commonly known as “spam”), and other malicious messages. Content filtering systems for combating malicious messages in general purpose computers, such as desktop computers and servers, are commercially available from several antivirus vendors. These content filtering systems, however, are generally too big and resource intensive for use in mobile phones. While mobile phones have become popular, they are still resource limited compared to general purpose computers. More particularly, most mobile phones have limited amounts of main memory (e.g., less than 1 MB), have relatively small file systems, and have slower CPU, which may or may not have floating point capability.